SEARCH · PubMed Health

Results for “Colocalization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources

PubMed1994

Cholinesterases colocalize with sites of neurofibrillary degeneration in aged and Alzheimer's brains.

Acetylcholinesterase and butyrylcholinesterase have been associated with structures undergoing neurofibrillary degeneration, as well as with all types of senile plaques, in non-demented aged and Alzheimer's brains. At the electron microscope level, the reaction product of both enzymes, appeared to decorate paired helical filaments, straight filaments and beta A4 amyloid fibrils. Recent studies showed that cholinesterases were associated with amyloid at early stages, e.g., in diffuse plaques. In the present study, the interrelationship of cholinesterases to structures undergoing neurofibrillary degeneration was analyzed further. Tau immunoreactivity was compared to the staining pattern observed with the two esterases. Double protocols consecutively performed on the same sections, and counterstaining with thioflavin-S, confirmed the presence of cholinesterases in all structures with neurofibrillary degeneration. The conclusion that cholinesterases consistently colocalize with both neurofibrillary bundles and beta A4 amyloid fibrils at all stages of their accumulation, allows us to speculate on the possible role that these enzymes may play in either the formation or the consolidation of fibrillary aggregates.

Acetylcholinesterase↗

PubMed1993

Ultrastructural localization of NADPH-diaphorase and colocalization of nitric oxide synthase in endothelial cells of the rabbit aorta.

This is the first report on the ultrastructural pattern of distribution of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) in endothelial cells, using the rabbit aorta, and its colocalization with the neuronal isoform (type I) of nitric oxide synthase. About 30% of the endothelial cells showed a positive reaction for NADPH-d compared to about 6% for nitric oxide synthase immunoreactivity. Simultaneous double histochemical-immunocytochemical labelling procedures indicate that all of the cells displaying nitric oxide synthase-positive reactivity also contained NADPH-d; the remainder of NADPH-d-positive endothelial cells were negative for this isoform of nitric oxide synthase. Nitric oxide synthase-immunogold labelling was mostly associated with free ribosomes, while NADPH-d activity was distributed largely in patches in the cytoplasm and in association with the cell membrane.

Amino Acid Oxidoreductases↗

PubMed1995

FMRFamide-like and allatostatin-like immunoreactivity in the lateral heart nerve of Periplaneta americana: colocalization at the electron-microscopic level.

Both allatostatin immunoreactivity (AS-IR) and FMRFamide immunoreactivity (FMRFa-IR) have been demonstrated light-microscopically in the lateral heart nerve of Periplaneta americana. The identical labeling of some fibers suggests the coexistence of the two antigens. Electron-microscopically, six granule types in the peripheral part of the lateral heart nerve can be distinguished according to their size and density (types 1-6). These granule types can be subdivided immunocytochemically by means of a new mirror-section technique. Granules of types 4 and 5 always exclusively show FMRFa-IR. In the populations of fibers containing granules of types 1 and 6, axon profiles can be found that contain granules colocalizing FMRFa-IR and AS-IR. Other axon profiles of these populations only contain immunonegative granules of the same ultrastructure. Granules of type 2 can be differentiated immunocytochemically in three forms in the same section: In some fibers, they are nonreactive; in other fibers of the same section, they show FMRFa - IR, whereas in a third fiber type, granules show AS - IR. Finally, granules of type 3 can be observed with FMRFa-IR. In other fibers, they occur with the same ultrastructure but exhibit no immunoreactivity. Two soma types occur in the lateral heart nerve. Soma type I is characterized by the production of electron-dense granules that show FMRFa-IR. Type II is in close contact with various fibers, forming different types of axosomatic synapses, hitherto unknown in Insecta.

Amino Acid Sequence↗

PubMed1993

Colocalization of cholinesterases with beta amyloid protein in aged and Alzheimer's brains.

The colocalization of beta amyloid protein with the enzymes acetyl- and butyrylcholinesterase was assessed using immunocytochemistry for beta amyloid protein and a sensitive histochemical technique for cholinesterases. In non-demented aged and Alzheimer's disease brains, double-stained sections for cholinesterases and thioflavin-S showed that all thioflavin-S-positive plaques were also positive for cholinesterases, indicating the presence of these enzymes in all plaques with beta-pleated amyloid protein. When amyloid angiopathy was present, cholinesterases were also observed in amyloid-laden vessels walls. Comparison of series of adjacent sections alternatively stained for acetylcholinesterase, beta amyloid protein and butyrylcholinesterase, as well as by double histo-immunocytochemical staining, showed either cholinesterase in a proportion of the preamyloid diffuse plaques. These data indicate that cholinesterases are associated with the amyloid protein from very early stages, when the beta-pleated structure is being formed. Novel functions attributed to acetyl- and butyrylcholinesterase, such us their proteolytic activity either by themselves or in association with heparan sulfate proteoglycans, may play a role in the aggregation or the consolidation processes taking place at the early stages of diffuse plaque formation.

Aged↗

PubMed1994

Distribution and colocalization of nitric oxide synthase and NADPH-diaphorase in adrenal gland of developing, adult and aging Sprague-Dawley rats.

The distribution and colocalization of nitric oxide synthase and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-diaphorase) was investigated in the adrenal gland of developing, adult and aging rats with the use of immunohistochemical and histochemical techniques. Nitric oxide synthase-immunoreactive neurons within the adrenal gland were found from the 20th day of gestation onwards. During early development the neurons were found as small clusters of smaller-size cells compared to those observed in the adult gland. Their number reached that of adult level by the 4th day after birth, and in the glands from aging rats a 28.6% increase was observed. Whilst no immunofluorescence was seen in chromaffin cells during early development, some cells from glands of aging rats showed nitric oxide synthase-immunoreactivity with varying intensity. The immunoreactive neurons from postnatal rat adrenals were also positive for NADPH-diaphorase, whilst those in prenatal rats were negative or lightly stained. Nitric oxide synthase-immunoreactive nerve fibres were present in all adrenal glands examined from the 16th day of gestation onwards. A considerable degree of variation in the distribution of immunoreactive fibres both in medulla and outer region of cortex at the different age groups was observed and described. Most, but not all, nitric oxide synthase-immunoreactive nerve fibres also showed NADPH-diaphorase staining.

Adrenal Glands↗

PubMed1987

Immunohistochemical colocalization of growth hormone (GH) and alpha subunit in human GH secreting pituitary adenomas.

This immunohistochemical study disclosed that 9 of 15 GH secreting pituitary adenomas contained alpha subunit positive cells. These cases also contained PRL positive adenoma cells, but LH beta was negative. Of these 9 cases, 4 cases showed occasional FSH beta containing cells, 2 of these also contained a few TSH beta positive cells. By mirror section technique, variable numbers of adenoma cells were found to contain both GH and alpha subunit. Immunoelectron microscopically, both GH and alpha subunit were localized in secretory granules which suggested their co-release from the tumour cells. The presence of GH and alpha subunit in rough endoplasmic reticulum indicated their active production in the tumour. In the normal adult anterior pituitary gland, about 10% of GH cells contain FSH alpha, beta and LH beta subunits and had appearances suggesting the co-production of GH and FSH as well as LH. The colocalization of GH and FSH alpha is considered to be associated with the neoplastic transformation GH cells which possess the intrinsic potentiality of differentiation toward alpha subunit. However, the mechanism for the lack or deficiency of beta subunits in the neoplastic condition remains to be further investigated.

Adenoma↗

PubMed1995

Ultrastructural colocalization of phosphorylcholine and a phosphorylcholine-associated epitope in first-stage larvae of Trichinella spiralis.

Although the presence of phosphorylcholine (PC) in Trichinella is well established, the structures of the TSL-4 antigens that bear this epitope are unknown. A subset of TSL-4 antigens (TSL-8 antigens) has been reported to be absent from the surface of first-stage T. spiralis larvae. We report experiments with a monoclonal antibody (mAb US2) developed in mice with a relative inability to produce antibodies to PC. In immunoblotting, mAb US2 and anti-PC mAb (BH8) showed apparently identical binding patterns. In addition, we used an immunogold double-labeling technique to study the anatomical distribution of the epitopes recognized by these mAbs; the results obtained indicate close colocalization of epitopes for BH8 and US2 in tissues of T. spiralis first-stage larvae. On the basis of these results, we suggest that US2 probably binds to all T. spiralis TSL-4 antigens, including TSL-8 antigens. We also clarify some conflicting previous reports on the distribution of PC immunoreactivity in first-stage larvae of T. spiralis.

Animals↗

PubMed1990

GABA neurons in the rat suprachiasmatic nucleus: involvement in chemospecific synaptic circuitry and evidence for GAD-peptide colocalization.

Dual labelling methods were employed for the electron microscopic detection of glutamate decarboxylase (GAD) immunoreactivity, together with vasoactive intestinal peptide (VIP) or neuropeptide Y (NPY) immunoreactivity in the suprachiasmatic nucleus (SCN) of colchicine pretreated and untreated rats. These methods involved the combined use of diaminobenzidine and benzidine dihydrochloride as distinct chromogens to visualize peroxidase-anti-peroxidase (PAP) immunostaining, and a combination of the PAP procedure with a radioimmunocytochemical method employing 125I-labelled secondary antisera. We were thereby able to demonstrate that gamma-aminobutyric acid (GABA) terminals provide an important afferent synaptic input to VIP neurons. Some of these VIP-immunoreactive neurons also exhibited GAD immunoreactivity. Examples of direct appositions between GABA and NPY terminals, and of a convergence of the two types of terminals on to the same postsynaptic targets, were frequently encountered. NPY/GAD colocalization within a few axonal varicosities was also demonstrated. These data provide additional information concerning chemospecific neuronal interactions that could be of functional importance in the regulation of circadian rhythmicity at the level of the SCN.

Animals↗

PubMedDate not supplied

Immunocytochemical colocalization of histamine, histidine decarboxylase, 5-hydroxytryptamine and tyrosine hydroxylase in the superior cervical ganglion of the rat.

The coexistence of histamine, histidine decarboxylase (the enzyme synthesizing histamine), 5-hydroxytryptamine and tyrosine hydroxylase (the rate-limiting enzyme in catecholamine synthesis), was studied in the rat superior cervical ganglion with the indirect immunofluorescence method. Possible colocalization was examined by staining consecutive sections with two different antibodies, or alternatively in the same section by eluting the first antibody with a mild solution containing potassium permanganate and sulphuric acid, and by staining the same section with another antibody. It was shown that tyrosine hydroxylase immunoreactivity was found both in large principal nerve cells and in small cells, which on the basis of their size and high nucleus-cytoplasm ratio corresponded to small intensely fluorescent (SIF) cells. Histamine, histidine decarboxylase and 5-hydroxytryptamine immunoreactivities were observed only in SIF cells. Those SIF cells which were immunoreactive for histamine, histidine decarboxylase or 5-hydroxytryptamine also contained tyrosine hydroxylase immunoreactivity. On the other hand, all tyrosine hydroxylase-immunoreactive SIF cells were also immunoreactive for histidine decarboxylase or 5-hydroxytryptamine. Some of the SIF cells, which were non-reactive for histamine, were immunoreactive for tyrosine hydroxylase.

Animals↗

PubMed1990

Distribution of FMRFamide-like immunoreactivity in the brain and suboesophageal ganglion of the sphinx moth Manduca sexta and colocalization with SCPB-, BPP-, and GABA-like immunoreactivity.

Using an antiserum against the tetrapeptide FMRFamide, we have studied the distribution of FMRFamide-like substances in the brain and suboesophageal ganglion of the sphinx moth Manduca sexta. More than 2000 neurons per hemisphere exhibit FMRFamide-like immunoreactivity. Most of these cells reside within the optic lobe. Particular types of FMRFamide-immunoreactive neurons can be identified. Among these are neurosecretory cells, putatively centrifugal neurons of the optic lobe, local interneurons of the antennal lobe, mushroom-body Kenyon cells, and small-field neurons of the central complex. In the suboesophageal ganglion, groups of ventral midline neurons exhibit FMRFamide-like immunoreactivity. Some of these cells have axons in the maxillary nerves and apparently give rise to FMRFamide-immunoreactive terminals in the sheath of the suboesophageal ganglion and the maxillary nerves. In local interneurons of the antennal lobe and a particular group of protocerebral neurons, FMRFamide-like immunoreactivity is colocalized with GABA-like immunoreactivity. This suggests that FMRFamide-like peptides may be cotransmitters of these putatively GABAergic interneurons. All FMRFamide-immunoreactive neurons are, furthermore, immunoreactive with an antiserum against bovine pancreatic polypeptide, and the vast majority is also immunoreactive with an antibody against the molluscan small cardioactive peptide SCPB. Therefore, it is possible that more than one peptide is localized within many FMRFamide-immunoreactive neurons. The results suggest that FMRFamide-related peptides are widespread within the nervous system of M. sexta and might function as neurohormones and neurotransmitters in a variety of neuronal cell types.

Animals↗

PubMed1990

Colocalization of estrogen and progesterone receptors with an estrogen-regulated heat shock protein in paraffin sections of human breast and endometrial cancer tissue.

We have studied by immunocytochemistry and monoclonal antibodies the presence and localization of estrogen receptors, progesterone receptors, and a 24-kD estrogen-regulated heat shock protein in biopsies from breast and endometrial cancer patients. Three different tissue processing protocols were used to colocalize the antigens in the same tissue sections: a) frozen sections, b) formalin fixation with routine paraffin embedding, and c) picric acid-formaldehyde (PAF) fixation with a rapid embedding in paraffin. Frozen sections showed good receptor staining but poor 24-kD protein immunoreactivity, while routine paraffin sections (with or without DNase pretreatment) were inadequate to reveal the nuclear receptor proteins at the same level seen in frozen sections. On the other hand, all three proteins could be detected satisfactorily in PAF-fixed paraffin-embedded tissue. Using this procedure we were able to visualize 24-kD protein and estrogen receptor or progesterone receptor in individual cells in paraffin sections. The study revealed that in all of the estrogen receptor positive breast and endometrial tumor samples, almost 90% of the cells expressing the cytoplasmic 24-kD protein contained estrogen receptor in the cell nucleus. In contrast, 24-kD immunoreactive cells did not express progesterone receptors in almost 40% of the progesterone receptor positive tumor samples.

Adenocarcinoma↗

PubMed1997

Divergent Subcellular Locations of HTLV-I Tax and Int-6: A Contrast between in vitro Protein-Protein Binding and Intracellular Protein Colocalization.

Protein-protein interactions define many important molecular and cellular processes in prokaryotic and eukaryotic biology. In trying to delineate the contact between two proteins, the yeast two-hybrid assay has emerged as a powerful technique. Complementing the yeast two-hybrid assay are in vitro techniques (e.g. GST-fusion-protein chromatography) that can also yield information on protein-protein associations. However, unambiguous functional significance to these interactions is best supported through a finding of colocalization of two proteins inside cells. In instances where two proteins interact in vitro but have divergent localizations within cells one needs to reconsider the biological importance of the former finding. Here, we present evidence for different subcellular locations of HTLV-I Tax and the Int-6 protein. We suggest a reexploration of the functional significance between Tax and Int-6 in cellular transformation.

Journal Article↗

PubMed2003

Colocalization of cortical microtubules and F-actin in Dipodascus magnusii using confocal laser scanning microscopy.

Distribution of microtubules and F-actin in aerobically growing cells of Dipodascus magnusii, belonging to the class Saccharomycetes was analyzed using immunofluorescence microscopy and labeling with rhodamine-tagged phalloidin. A conspicuous system of permanent cytoplasmic microtubules was observed in association with multiple nuclei. In elongating cells, helices of cytoplasmic microtubules appeared at the cell cortex. In cells approaching cytokinesis transversely oriented microtubules were revealed at incipient division sites. Confocal laser scanning microscopy showed a continuity of these transverse microtubules with the remaining microtubule network. The actin system of D. magnusii consisted of patches and filaments. Patches were found to accumulate at the tips of growing cells. Bands of fine actin filaments were usually observed before F-actin rings were established. A close cortical association of microtubules with the F-actin ring was documented on individual optical sections of labeled cells. Cells with developing septa showed medial F-actin discs associated at both sides with microtubules. Colocalization of cytoplasmic microtubules with actin filaments at the cortex of dividing cells supports a role of both cytoskeletal components in controlling cell wall growth and septum formation in D. magnusii.

Actins↗

PubMed1998

The marginal nuclei of the spinal cord in turtles: neuron assemblies in which gamma-aminobutyric acid and nitric oxide synthase are colocalized.

Conspicuous nerve-cell assemblies, identified as the marginal nuclei described in other sauropsidans, were found all along the spinal cord of turtles. gamma-aminobutyric acid (GABA) and nitric oxide synthase (NOS) activities were colocalized within these neurons, which also reacted positively to reduced nicotinamide adenine dinucleotide phosphate-diaphorase stains. The marginal nuclei neurons may, thus, play an inhibitory function mediated by their GABA terminals and a long-distance modulatory function mediated by NO liberation.

Animals↗

PubMed2003

Persistent eIF2alpha(P) is colocalized with cytoplasmic cytochrome c in vulnerable hippocampal neurons after 4 hours of reperfusion following 10-minute complete brain ischemia.

Upon brain reperfusion following ischemia, there is widespread inhibition of neuronal protein synthesis that is due to phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha), which persists in selectively vulnerable neurons (SVNs) destined to die. Other investigators have shown that expression of mutant eIF2alpha (S51D) mimicking phosphorylated eIF2alpha induces apoptosis, and expression of non-phosphorylatable eIF2alpha (S51A) blocks induction of apoptosis. An early event in initiating apoptosis is the release of cytochrome c from mitochondria, and cytochrome c release corresponds to the selective vulnerability of hippocampal CA1 neurons in rats after transient global cerebral ischemia. At present the signaling pathways leading to this are not well defined. We hypothesized that persistent eIF2alpha(P) reflects injury mechanisms that are causally upstream of release of cytochrome c and induction of apoptosis. At 4 h of reperfusion following 10-min cardiac arrest, vulnerable neurons in the striatum, hippocampal hilus and CA1 showed colocalized intense immunostaining for both persistent eIF2alpha(P) and cytoplasmic cytochrome c, while resistant neurons in the dentate gyrus and elsewhere did not immunostain for either. A lower intensity of persistent eIF2alpha(P) immunostaining was present in cortical layer V pyramidal neurons without cytoplasmic cytochrome c, possibly reflecting the lesser vulnerability of this area to ischemia. We did not observe cytoplasmic cytochrome c in any neurons that did not also display persistent eIF2alpha(P) immunostaining. Because phosphorylation of eIF2alpha during early brain reperfusion is carried out by PERK, these findings suggest that there is prolonged activation of the unfolded protein response in the reperfused brain.

Animals↗

PubMed2003

Familial British dementia: colocalization of furin and ABri amyloid.

Familial British dementia (FBD) is an autosomal dominant condition caused by a point mutation in the stop codon of the BRI gene. This mutation extends the normal precursor protein (PP) of 266 amino acids to the next stop codon, which is at amino acid 277. Kim and colleagues demonstrated in vitro that furin can process both the normal protein BriPP and the extended protein ABriPP to produce C-terminal fragments of 23 and 34 amino acids. The abnormal C-terminal fragment, ABri, accumulates in FBD in the form of extracellular amyloid deposits. The objective of our study was to determine if furin is associated with ABri in FBD. Brain tissue of one case of FBD, four cases of Alzheimer's disease (AD) and two controls were studied by immunohistochemistry using antibodies against furin, beta-amyloid protein and ABri. In FBD, furin was found to be colocalized with ABri deposits and amyloid angiopathy in all areas examined. In contrast beta-amyloid deposits in AD were not immunostained by the furin antibody. In normal as well as pathological cases, clusters of neurons in the hippocampus and neocortex showed light to moderate furin immunostaining, while peptidergic neurons of the hypothalamus showed intense furin-immunostaining. These data suggest that furin may be involved in producing the pathological fragment of ABriPP in vivo and that inhibition of furin might be a method of treating this disorder.

Aged↗

PubMed1997

p35nck5a and cyclin-dependent kinase 5 colocalize in Lewy bodies of brains with Parkinson's disease.

We examined the immunohistochemical localization of p35nck5a, the regulatory subunit of cyclin-dependent kinase 5 (cdk5), in brains obtained postmortem from patients with Parkinson's disease (PD) and controls. We found p35nck5a immunoreactivity in Lewy bodies (LB) in the substantia nigra, locus ceruleus, and neocortex of brains from patients with PD. In addition, p35nck5a was colocalized with cdk5 immunoreactivity in LB. Cdk5 is the kinase most likely to be responsible for the phosphorylation of neurofilament proteins of LB, which is a crucial step for the formation of the insoluble LB fibrils. Since p35nck5a regulates the catalytic activity of cdk5 by forming a heterodimer with cdk5, the present results strongly support the hypothesis that a cdk5-p35nck5a complex is involved in the formation of LB fibrils.

Aged↗

PubMed1998

HLA-DM is expressed on the cell surface and colocalizes with HLA-DR and invariant chain in human Langerhans cells.

The subcellular distribution patterns of molecules involved in the process of antigen loading [HLA-DR, HLA-DM, and the cytoplasmic and luminal parts of the invariant chain (Ii, CD74)] were investigated in Langerhans cells (LC), both qualitatively and quantitatively. The analysis was performed by immunofluorescence labelling of acetone-fixed vertical cryostat sections from normal human skin specimens and subsequent examination using confocal laser scanning microscopy (CSLM). The intensity-modulated multiple-wavelength scanning (IMS) technique was used to enhance channel separation when scanning dual-labelled specimens. The mean (n = 9) relative epidermal volumes of reactivity were: HLA-DR 8%+/-3%, HLA-DM 6%+/-2%, luminal Ii 6%+/-2%, and cytoplasmic Ii 4%+/-1%. The difference between HLA-DR and the other epitopes was significant at the P<0.001 level. All molecule combinations, except the combination of HLA-DM and luminal Ii (which was not studied), were to various extents colocalized. Experiments performed on unfixed epidermal sheets showed that HLA-DM is present on the cell surface of LC, suggesting that HLA-DM may interact with HLA-DR on the surface to induce peptide loading.

Adult↗